Heating/Air-Conditioning Installation With External And Contiguous Condenser And Evaporator For Heating The External Evaporator

ABSTRACT

A heating/air-conditioning installation (IC) comprises a compressor (CP) capable of heating and pressurizing a refrigerant, an internal condenser (CDI) capable, in heating mode, of contributing towards the heating of an air known as interior air by exchange with the refrigerant coming from the compressor (CP), an external pressure reducer (DTE) capable, in heating mode, of cooling the refrigerant, and an external evaporator (EE) capable, in heating mode, of heating up the refrigerant coming from the external pressure reducer (DTE) by exchange of heat with an air known as exterior air to feed into the compressor (CP). This installation (IC) further comprises an external condenser (CDE) contiguous with the external evaporator (EE) and capable, in heating mode, of collecting the refrigerant coming from the internal condenser (CDI) to feed the external pressure reducer (DTE) and constitute a heat source for the contiguous external evaporator (EE), so as to reduce the probability of the latter (EE) icing up in the presence of exterior air at a low temperature.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the US national stage under 35 U.S.C. §371 ofInternational Application No. PCT/FR2011/050920 having an internationalfiling date of Apr. 21, 2011, which claims the priority of Frenchapplication 1054015 filed on May 25, 2010.

BACKGROUND

The invention relates to the heating/air conditioning installations thatequip certain vehicles, such as automobiles, as well as certainbuildings.

As is known to the person skilled in the art, certain heating/airconditioning installations include reversible heat pumps that are ableto work both in a heating mode as well as in a cooling mode. Inparticular, for this effect, they comprise an internal condenser which,in the heating mode, contributes towards heating of interior air byexchange with a heated and pressurized refrigerant fluid, and anexternal evaporator which, in the heating mode, heats the cooled anddepressurized refrigerant fluid by exchange with exterior air.

We will hereinafter understand “external” to indicate a device that isused in the heat exchange process with the exterior air (i.e. anexternal evaporator or an external pressure reducer that feeds aninternal evaporator), and understand “internal” to indicate a deviceused in the heat exchange process with the interior air (such as forexample an internal condenser or an internal evaporator or even aninternal pressure reducer which is feeding an internal evaporator).

In the event in which it is cold or very cold, which is to say when thetemperature of the exterior air is sub-zero or approaching zero degreesCelsius (0° C.), the contact between the exterior air and the partiallycooled refrigerant, which comes from the internal condenser and whichcirculates in the external evaporator, frequently provokes icing of theexternal evaporator, which has a negative impact on the functioning andtherefore renders the installation less effective.

Many solutions have been proposed to rectify this disadvantage.

Thus, a first solution, which is most notably described in the FrenchPat. No. FR 2525330, consists of associating conduits to the externalevaporator that are dedicated to de-icing in which a heat transfer fluidcoming from the cooling circuit (for example, from a vehicle motor)circulates. The disadvantage of this first solution lies in the factthat this requires an important modification of the external evaporator.Furthermore, it turns out to be very difficult to use when the heattransfer fluid is practically nonexistent or unavailable from an energyprospective in heating mode, as is notably the case in “all electric” or“hybrid” vehicles or in buildings.

A second solution, most notably described in the British Pat. No. GB988874, consists of implanting the external evaporator within the samehousing as the internal condenser, in such a manner that the externalevaporator can be heated due to the refrigerant liquid that iscirculating in the internal condenser. The disadvantage of this secondsolution lies in the fact that it is exceedingly inconvenient, or evenimpossible to implement in an automobile and has a negative impact onoverall performance.

A third solution that is notably described in the U.S. Pat. No.5,586,448 consists in the use of an additional electric radiator for theheating of a heat transfer fluid which circulates through the externalevaporator. The disadvantage of this third solution lies in the factthat it requires not only a modification of the external evaporator, butalso an additional electric heating device, which reveals itself to bevery cumbersome and energy hungry (which is penalizing as regards rangein the case of an electric or hybrid vehicle).

SUMMARY

The object of the invention is therefore to propose a heating/airconditioning installation that does not present all or parts of theaforementioned disadvantages.

In particular, in this vein, a heating/air conditioning installation orsystem is provided that comprises:

-   -   A dedicated compressor for the heating and pressurization of a        refrigerant fluid,    -   A dedicated internal condenser which, in heating mode, will        contribute to the heating of interior air through exchange with        the refrigerant fluid coming from the compressor,    -   A dedicated external pressure reducer which, in heating mode,        will cool the refrigerant fluid (before it feeds the external        evaporator),    -   A dedicated external evaporator which, in heating mode, will        heat the refrigerant fluid coming from the external pressure        reducer by exchange of exterior air to feed the compressor, and    -   An external condenser that is contiguous to the external and        dedicated evaporator which, in heating mode, will collect the        refrigerant fluid that comes from the internal condenser to feed        the external pressure reducer and make up a heat source for the        contiguous external evaporator, in such a manner as to reduce        the probability that the external evaporator will ice up in the        presence of an exterior air at a low temperature.    -   The external condenser collects refrigerant fluid at its inlet        that comes from the internal condenser in a partial gaseous and        partially liquid form so as to provide, at its outlet, a        refrigerant fluid in liquid form. At the inlet of the internal        condenser, the refrigerant fluid is in gaseous form. The        condensation of the refrigerant fluid from the gaseous phase        towards the liquid phase is therefore carried out in two parts,        a first part at the level of the internal condenser, which is        followed by the second part at the level of the external        condenser. When compared to a simple bit of hosing that        transports the refrigerant fluid in liquid form, the presence of        the external condenser allows the transmission of more calories        and therefore more heat to the external evaporator, which        further diminishes the risk of icing up of the external        evaporator.

The heating/air conditioning installation can also feature othercharacteristics that can be taken either separately or in combination,and more in particular:

-   -   Its external condenser and its external evaporator can make up        two contiguous sub-units of a same heat exchanger or two        independent and contiguous heat exchangers;    -   It can feature a dedicated internal pressure reducer which, in        refrigeration mode, will cool the refrigerant fluid, and a        dedicated internal evaporator which, in refrigeration mode, will        cool the interior air by exchange with the refrigerant fluid        coming from the internal pressure reducer;    -   Its external condenser can be dedicated, in refrigeration mode,        to pre-cool the refrigerant fluid coming from the compressor by        exchange with the exterior air, so as to supply the internal        pressure reducer with pre-cooled refrigerant fluid;    -   It can feature a first three-way valve which includes a first        inlet coupled with the output of the compressor, a first outlet        coupled with the input of the compressor and a second outlet        coupled with a first inlet/outlet of the external condenser;    -   It can feature a second three-way valve which includes an inlet        coupled with the outlet of the internal condenser, an outlet        coupled with the inlet of the internal evaporator, and        inlet/outlet coupled to a second inlet/outlet of the external        condenser;    -   It can feature a third three-way valve which includes a first        inlet coupled with the second outlet of the first valve, an        outlet coupled with the inlet of the external pressure reducer,        and an inlet/outlet coupled with the first inlet/outlet of said        external condenser;    -   It can feature a fourth three-way valve which includes a first        inlet coupled with the outlet of the internal evaporator, a        second inlet coupled with the outlet of the external evaporator,        and an outlet coupled with the inlet of the compressor;    -   Its internal condenser can be dedicated, in heating mode, to        heat the interior air by exchange with the refrigerant fluid        coming from the compressor;    -   As an alternative, its internal condenser may be dedicated, in        heating mode, to heat, by exchange with the refrigerant fluid        which comes from the compressor, a heat transfer fluid which is        destined to feed a dedicated air heater to heat the interior air        by thermal exchange.

The invention furthermore proposes a vehicle, such as an automobile,which features a heating/air conditioning installation of the typedescribed here above.

DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will be revealedupon examination of the following detailed description, as well as fromthe attached drawings, in which:

FIG. 1 illustrates a first embodiment in a schematic and functional formof a heating/air conditioning installation, in heating mode,

FIG. 2 illustrates a second embodiment in a schematic and functionalform of a heating/air conditioning installation, in heating mode, and

FIG. 3 illustrates, in a schematic and functional form, the heating/airconditioning installation of FIG. 1, in refrigeration mode.

The attached drawings can, as the case may be, help to complement theinvention, as well as to contribute to its definition.

DETAILED DESCRIPTION

The purpose of the invention is that of proposing a reversible heat pumpheating/air conditioning installation (IC).

We consider hereinafter as a non-exhaustive example, that theheating/air conditioning installation (IC) belongs to an automobile,such as for example, a car, such as the “full electric” or “hybrid”type. However, the invention is not limited to this application. It doesin fact involve any reversible heat pump type heating/air conditioninginstallation, no matter whether it is destined to be installed in avehicle or a building.

Two embodiments of heating/air conditioning installations IC, accordingto the invention, are schematically represented in FIGS. 1-3. The firstembodiment, illustrated in FIGS. 1 and 3, is, for example, destined tobe installed in an electric automobile or in a building. The secondembodiment, illustrated in FIG. 2 is for example destined to beimplanted in a hybrid automobile.

The heating/air conditioning installation IC is destined to work, asrequired, in heating or refrigeration mode. In particular, for thispurpose, it features a compressor CP, an internal condenser CDI, anexternal pressure reducer DTE, an external evaporator EE, and anexternal condenser CDE that all are used, at least, in the heating mode.

The compressor CP heats and pressurizes a refrigerant fluid which, inheating mode, comes from the external evaporator EE.

The internal condenser CDI is only used in the heating mode. Itcontributes to the heating of the interior air (which here comes fromthe interior of the vehicle cabin) by exchange with the refrigerantfluid transformed into hot and pressurized gas by the compressor CP. Atits outlet, it delivers a refrigerant fluid in liquid phase that hasbeen partially cooled during exchange with the interior air.

In the example illustrated in FIGS. 1 and 3, the internal condenser CDIis of the gas/air type. It is therefore used to heat the interior airwhich passes through it by exchange with the refrigerant fluid (hot andpressurized gas) which circulates in its conduits or between its stackedpanels.

In the example illustrated in FIG. 2, the internal condenser CDI is ofthe gas/liquid type. It therefore heats a heat transfer fluid, whichcirculates in some of its conduits or between certain parts of itsstacked panels and which comes from a cooling circuit, by exchange withthe refrigerant fluid (hot and pressurized gas) which circulates incertain other of its conduits or between certain other parts of itsstacked panels. This heated heat transfer fluid then returns to thecooling circuit to feed a pump PE, which feeds an air heater AR which,in heating mode, heats the interior air which passes through it byexchange with the heated heat transfer fluid. Conventionally, the heattransfer fluid which flows out of the air heater AR feeds the portion ofthe cooling circuit which passes through the motor MR and which feedsthe internal condenser CDI.

Herein, “air heater” is understood to mean an air/liquid heat exchanger.Furthermore, one will note that the air heater AR can form part of theinstallation IC.

The external pressure reducer DTE is only used in the heating mode. Itcools and depressurizes the refrigerant fluid which comes from theexternal condenser CDI, before it feeds the external evaporator EE. Itdelivers a depressurized and cooled liquid.

The external evaporator EE is only used in the heating mode. It is usedin heating the refrigerant fluid (depressurized and cooled liquid) whichcomes from the external pressure reducer DTE, by exchange with theexterior air (cold), which is to say absorption of heat contained in theexterior air. It delivers a refrigerant fluid at the outlet, in gaseousand lightly heated phase, which is destined to feed the compressor CP.

The external condenser CDE is contiguous with the external evaporatorEE.

Herein, “contiguous” is understood to be the fact of being in contactwith the external evaporator EE, or in the immediate vicinity of theexternal evaporator, most typically within a few centimeters, or ratherinterlocked in the external evaporator EE.

The external condenser CDE, in heating mode, collects the refrigerantfluid, which comes from the internal condenser CDI, so as to feedtogether with this refrigerant fluid, the external pressure reducer DTEand constitutes a heat source for the contiguous external evaporator EE.One will then understand that this source of heat (which is made up ofthe external condenser CDE) is such that it will reduce the probabilitythat the external evaporator EE will ice up in the presence of anexterior air whose temperature is low.

Herein, “reducing the probability of icing” is understood to be the factof limiting, as much as is possible, the creation of icing as regardsthe external evaporator EE. Typically, icing up will only be able tooccur in the presence of a low exterior temperature, with a high levelof humidity and a low exterior air speed.

It is important to note that the heating of the external evaporator EEcan be undertaken by thermal conduction, in the case of an interlocking,or mechanical contact, with the external condenser CDE, and/or by meansof the exterior air which has been heated during its passing through theexternal condenser CDE (which requires that the external condenser beplaced upstream of the external evaporator EE vis-â-vis the flow ofexterior air, as illustrated).

One will note that the external condenser CDE and the externalevaporator EE may constitute two contiguous sub-units (preferably,interlocking) of a single heat exchanger or two independent andcontiguous heat exchangers.

One will also note that the external condenser CDE may also function inthe cooling mode. In such a case, the installation must also include aninternal pressure reducer DTI and an internal evaporator EI, asillustrated in FIGS. 1-3.

The internal pressure reducer DTI is only used in the cooling mode. Itcools and pressurizes the refrigerant fluid (in liquid phase), whichcomes from the external condenser CDE, before it arrives at the internalevaporator EI.

The internal evaporator EI also is only used in the cooling mode. It isused to cool the interior air which passes through it by thermalexchange with the cooled and depressurized refrigerant fluid (in liquidphase) which comes from the internal pressure reducer DTI.

In the cooling mode, the external condenser CDE is used to pre-cool therefrigerant fluid (hot and pressurized gas), which comes from thecompressor CP, by thermal exchange with the exterior air, so as to feedthe internal pressure reducer DTI with pre-cooled refrigerant fluid (inliquid phase).

So as to facilitate the verification of the functioning of theinstallation IC, as well as to also limit its footprint, theheating/air-conditioning installation (IC) can include at least one ofthe three-way valves Vj, that are described here-below:

-   -   first valve V1 (j=1) that features an inlet coupled to the        outlet of the compressor CP, a first outlet coupled with the        inlet of the internal condenser CDI and a second outlet coupled        with a first inlet/outlet of the external condenser CDE.    -   second valve V2 (j=2) that features an inlet coupled to the        outlet of the internal condenser CDI, an outlet coupled with the        inlet of the internal evaporator EI and an inlet/outlet coupled        with a second inlet/outlet of the external condenser CDE.    -   A third valve V3 (j=3) that features a first inlet coupled with        the second outlet of the first valve V1, an outlet coupled to        the inlet of the pressure reducer DTE, and an inlet/outlet        coupled to the first inlet/outlet of the external condenser CDE.    -   A fourth valve V4=4) featuring a first inlet coupled with an        outlet of the internal evaporator EL a second inlet coupled with        the outlet of the external evaporator EE, and an outlet coupled        with the inlet of the compressor CP.

One will also note that, as is illustrated in a non-exhaustive manner inFIGS. 1-3, the installation IC can optionally include one or moredehydrating reservoirs RD1, RD2. In the examples illustrated, theinstallation IC features a first dehydration reservoir RD1 positionedbetween the first inlet/outlet of the external condenser CDE and theinlet of the external pressure reducer DTE, and a second dehydrationreservoir RD2 positioned between the second inlet/outlet of the externalcondenser CDE and the inlet of the internal evaporator EI.

The mode of heating of the installation IC is symbolized by arrows inFIGS. 1-2. In this heating mode, the refrigerant fluid circulates fromthe compressor CP towards the internal condenser CDI where it is used(FIG. 1) or simply contributes (FIG. 2) to the heating of the interiorair by thermal exchange. The first valve V1 is then configured in such away that the refrigerant fluid is directed towards the internalcondenser CDI. Thereafter, the refrigerant fluid goes from the internalcondenser CDI towards the external condenser CDE, by way of the secondvalve V2 which is configured for this purpose. It then heats thecontiguous external evaporator EE and thereby permits that it is eithernot or only slightly iced up. Then the refrigerant fluid goes from theexternal condenser CDE towards the external pressure reducer DTE, by wayof a third valve V3 which is configured for this purpose. It is thenpartially cooled and depressurized. Then, the refrigerant fluid goesfrom the external pressure reducer DTE towards the external evaporatorEE where it is cooled by thermal exchange with the exterior air. Lastly,the refrigerant fluid goes from the external evaporator EE towards thecompressor CP where it is transformed in to heated and pressurized gas,by way of a fourth valve V4 which is configured for this purpose.

The cooling mode of the installation IC is symbolized by arrows in FIG.3. In this cooling mode, the refrigerant fluid circulates from thecompressor CP towards the external condenser CDE where it is partiallycooled by thermal exchange with the exterior air. The first valve V1 andthe third valve V3 are configured for this purpose. Then, therefrigerant fluid goes from the external condenser CDE towards theinternal pressure reducer DTI where it is cooled and depressurized, byway of the second valve V2 which is configured for this purpose. Then,the refrigerant fluid goes from the internal pressure reducer DTItowards the internal evaporator EI where it cools the interior air thatpasses through the same (EI) by thermal exchange. Then, the refrigerantfluid goes from the internal evaporator EI towards the compressor CPwhere it is transformed in heated and pressurized gas, by way of thevalve V4 which is configured for this purpose.

The invention offers a certain number of advantages, amongst which:

-   -   It does not require any additional heating device, which is        particularly advantageous in the event of fitting in an        all-electric or hybrid system.    -   It allows for the improvement of the yield (performance        coefficient) of the thermodynamic cycle of the installation when        the exterior temperature is cold, or rather very cold, without        noticeably increasing its complexity, all the while decreasing        the enthalpy at the inlet of the external evaporator, thereby        permitting one to increase the evaporation energy of the latter        while maintaining the same throughput of refrigerant fluid and        therefore with the same quantity of consumed energy.

The invention does not limit itself to methods of execution of theheating/air conditioning installation and of the vehicle described hereabove, in a non-exhaustive manner, but rather encompasses all variantsthat could be foreseen by the person skilled in the art within theframework of the claims that follow.

1. A heating/air conditioning system comprising a compressor (CP)adapted to heat and pressurize a refrigerant fluid, an internalcondenser (CDI) capable, in a heating mode, to contribute to the heatingof interior air by exchange with said refrigerant fluid coming from saidcompressor (CP), an internal pressure reducer (DTE) capable, in aheating mode, to cool said refrigerant fluid coming from said externalpressure reducer (DTE) by exchange with exterior air to feed saidcompressor (CP), characterized in that it further comprises an externalcondenser (CDE) that is contiguous with said external evaporator (EE)which is capable, in a heating mode, of collecting said refrigerantfluid coming from said internal condenser (CDI) to feed said externalpressure reducer (DTE) and constitute a heat source for said contiguousexternal evaporator (EE), in such a manner as to reduce the probabilitythat the external evaporator (EE) will ice up in the presence ofexterior air that presents a low temperature.
 2. The system according toclaim 1, characterized in that said external condenser (CDE) and saidexternal evaporator (EE) make up two contiguous sub-units of a singleheat exchanger.
 3. The system according to claim 1, characterized inthat said external condenser (CDE) and said external evaporator (EE)make up two independent and contiguous heat exchangers.
 4. The systemaccording to claim 1, characterized in that it said system comprises aninternal pressure reducer (DTI) capable, in a cooling mode, to cool saidrefrigerant fluid, and an internal evaporator (EI) capable, in a coolingmode, to cool said interior air by exchange with said refrigerant fluidcoming from said internal pressure reducer (DTI).
 5. The systemaccording to claim 4, characterized in that said external condenser(CDE) is capable, in a cooling mode, to pre-cool said refrigerant fluidcoming from said compressor (CP) by exchange with said exterior air, soas to feed said internal pressure reducer (DTI) with pre-cooledrefrigerant fluid.
 6. The system according to claim 1, characterized inthat it said system includes a first three-way valve (V1) including aninlet coupled with the outlet of said compressor (CP), a first outletcoupled with the inlet of said internal condenser (CDI) and a secondoutlet coupled with a first inlet/outlet of said external condenser(CDE).
 7. The system according to claim 6, characterized in that it thesystem includes a second three-way valve (V2) including an inlet coupledwith an outlet of said internal condenser (CDI), an outlet coupled withthe inlet of said internal evaporator (EI), and an inlet/outlet coupledwith a second inlet/outlet of said external condenser (CDE).
 8. Thesystem according to claim 7, characterized in that it contains a thirdthree-way valve (V3) including a first inlet coupled with a secondoutlet of said first valve (V1), an outlet coupled to the inlet of saidexternal pressure reducer (DTE), and an inlet/outlet coupled with saidfirst inlet/outlet of said external condenser (CDE).
 9. The systemaccording to claim 8, characterized in that the system includes a fourththree-way valve (V4) including a first inlet coupled with the outlet ofsaid internal evaporator (EI), a second inlet coupled with the outlet ofsaid external evaporator (EE), and an outlet coupled with the inlet ofsaid compressor (CP).
 10. The system according to claim 1, characterizedin that said internal condenser (CDI) is capable, in a heating mode, toheat said interior air by exchange with said refrigerant fluid comingfrom said compressor (CP).
 11. The system according to claim 1,characterized in that said internal condenser (CDI) is capable, in aheating mode, to heat, by exchange with said refrigerant fluid comingfrom said compressor (CP), a heat transfer fluid destined to feed adedicated air heater (AR) to heat said interior air by thermal exchange.12. A vehicle characterized in that it includes a heating/airconditioning system, said heating/air conditioning system comprising acompressor (CP) adapted to heat and pressurize a refrigerant fluid, aninternal condenser (CDI) capable, in a heating mode, to contribute tothe heating of interior air by exchange with said refrigerant fluidcoming from said compressor (CP), an internal pressure reducer (DTE)capable, in a heating mode, to cool said refrigerant fluid coming fromsaid external pressure reducer (DTE) by exchange with exterior air tofeed said compressor (CP), characterized in that it further comprises anexternal condenser (CDE) that is contiguous with said externalevaporator (EE) which is capable, in a heating mode, of collecting saidrefrigerant fluid coming from said internal condenser (CDI) to feed saidexternal pressure reducer (DTE) and constitute a heat source for saidcontiguous external evaporator (EE), in such a manner as to reduce theprobability that the external evaporator (EE) will ice up in thepresence of exterior air that presents a low temperature.